Conventionally, there is a communication system that reads (or writes) a user's IC card through electromagnetic induction (for example, Patent Document 1). The IC card of such a communication system is configured by an IC chip and an antenna coil having at least a contactless communication function, and the IC chip provided within the IC card implements transmission and reception of data by receiving driving power through signals transmitted from the reader/writer, receiving an analog signal transmitted from the reader/writer, converting the analog signal into a digital signal, and sending back a response signal. The contactless IC cards are used in various systems such as a transportation system, an electronic money system, an employee ID card system, and a physical distribution management system.
As a communication scheme using a contactless IC card, an electromagnetic coupling scheme, an electrostatic coupling scheme, an electromagnetic induction scheme, and a radio wave scheme are used depending on the communication frequency band, and the electromagnetic induction scheme is the mainstream for contactless IC communication systems in the form of a card.
However, since an antenna coil of an IC card is formed by etching or the like in electromagnetic induction communication systems, the cost thereof has been high.
On the other hand, there is a communication system that reads (or writes) a user's IC card through electrostatic coupling (for example, Patent Document 2).
However, the communication distance between the information storage medium and the reader/writer in the electrostatic coupling communication system is shorter than that in the electromagnetic induction communication system. Therefore, whereas the electromagnetic induction communication system initiates communication in a state where the information storage medium is at some distance from the reader/writer, the electrostatic coupling communication system does not initiate communication unless the information storage medium is substantially in close contact with the reader/writer. Therefore, even if the communication time between the information storage medium and the reader/writer is equal to the communication time in the electromagnetic induction communication system, the user actually feels the processing time as being longer by a period of time required for approximating the information storage medium to the reader/writer at a closer distance. As a result, if the electrostatic coupling communication system is utilized in, for example, an automatic ticket gate, the gate may be congested.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2000-123121
Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2009-135632